The present invention relates to a pneumatic edge trimming machine, and especially to a pneumatic edge trimming machine which can absorb dust in working.
Referring to FIGS. 5 and 6, a prior art electric edge trimming machine is illustrated. A base 9 is installed with a motor 91. A shaft of the motor 91 protrudes downwards to be connected to a cutting knife 92. A trench 93 is formed in the base 9. One end of the trench 93 is connected to be near the knife 92, while another end is connected to a tube 94 extending from the base 9. The tube 94 is utilized to be connected with a soft tube 95 of a dust absorber (not shown), so that as the knife 92 cuts a work piece, the dust can be absorbed by absorber and then flows through the trench 93, tube 94, and soft tube 95 to be absorbed to the absorber.
Referring to FIG. 6, a schematic cross sectional view of a prior art electric edge trimming machine is illustrated. Since the knife 92 protrudes from the bottom of the base 9 for trimming in cutting. The trench 93 is positioned to the base 9. Therefore from the position for cutting a work piece by the knife 92 to the opening of the trench 93 are bent with 90 degrees and the trench 93 to the tube 94 are bent through 90 degrees to enter into the soft tube 95 of the dust absorber. Furthermore, the dust accumulator is installed at a farther place, and is connected to the tube 94 through a soft tube 95, the absorbing force thereof is reduced at the bending portions in the flowing path. Therefore the effect of dust absorption is not preferred.
Moreover, the dust absorber must be bought additionally. It is not a fitting of the electric edge trimming machine, and thus, the cost is high.
The rotary speed of the motor 91 of an electric edge trimming machine is high. If the working piece is a large load and heat dissipation is bad in cutting, it is very possible that the rotor of the motor 91 will be burnt out or other parts have faults. Furthermore, the electric edge trimming machine has a high cost.
Accordingly, the primary object of the present invention is to provide a pneumatic edge trimming machine, wherein the periphery of the inner casing has via holes facing upwards. Since the place generating an absorbing force is relative near the work piece of the knife, the dust is strongly absorbed. The flow from the work piece of the knife to the tube through the inner casing and outer casing are smooth. Therefore the effect of absorbing dust automatically is high.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.